This is what a barrier to trade looks like

The line-ups for the Kazungula ferry start two or three kilometres from the water on either side of the Zambezi river. Each line up might be 150 trucks long. But the Kazungula crossing is served by just two pontoon ferries. Each ferry takes one truck, and makes the return journey in half an hour or so, transporting perhaps 20 or 25 trucks a day. The ferries often break down. When one is them is out of service, that 150 truck line-up might mean a week of waiting.

The Kazungula crossing is on one of the major trans-African highway corridors. There are other routes through to Southern Africa. To the east of Kazungula, bridges cross the Zambezi into Zimbabwe, but bureaucratic delays and corruption mean crossing in and out of Zimbabwe can be expensive and time consuming. Delays of two to five days and demands for "push money" are not uncommon. The once infamous Zambia-Zimbabwe crossing at Chirundu has recently been upgraded and, according to the African Development Bank, crossing there now takes only a few hours. However a recent report to the Zimbabwean parliament noted that the Chirundu air conditioning unit broke down one week after the new building opened, and power outages are still frequent (see here around p. 25).

To the west of Kazungula, the Katima Mulilo Bridge links Zambia with Namibia, and the western corridor down to Cape Town. Unfortunately this route means a detour of many hundreds of miles for a driver headed towards Durban or other points in the south east. In Africa, time is cheap, but gas is sold at international market prices. Saving fuel is more important than saving time.

So the drivers wait. And wait.

The long delays mean that commercial trade in perishable goods is impossible, hampering agricultural exports in Africa's many land-locked countries. Delays create hazards for drivers, who have to guard against thieves, who will rob them of goods or diesel fuel. (Drivers also have to navigate other dangers, such as snakes). Perhaps most seriously, bored and lonely drivers transport HIV/AIDS up and down the highway corridors, spreading the disease across the continent.

Given that Kazungula is such an important crossing point, why isn't there a bridge? Geography is part of the story. Kazungula is the nearest things on earth to a four-country quadripoint. Where the Chobe meets the Zambezi, the borders of four countries - Namibia, Zambia, Botswana, and Zimbabwe - almost touch. There has been talk of building a bridge for years, but the countries could never agree how to divide the costs. Zambia and Botswana are now going ahead and building a bridge without Zimbabwe's cooperation, and have lined up financing from a number of national and international institutions. The new bridge will actually be curved to avoid going over Zimbabwean waters.

Interest group politics are also part of the bridge-building story. The Katima Mulilo Bridge was built because a clearly defined interest group wanted it: Zambia is a major copper producer, and the bridge links the Zambian copper belt to ports in Namibia. But a bridge at Kazungula will serve a more diffuse and less politically powerful set of interests. There are few Zambian equivalents of the huge supermarket chains like Safeway or Loblaws, that lobby hard for better transport (though retailers like SPAR with a strong African presence might mention the subject occasionally). If a two-bit trucker going from Tanzania to Cape Town has to wait a few days, why should the Zambian or Botswanian government care?

The pressure for better transport links is dampened further by the fact that not everyone has to wait. Just like at Universal Studios, some people have front-of-the-line passes. While Lonely Planet types take the pontoon ferry, other tourists are whisked across the river on private boats.

People whose experience of international travel is limited to airports might think of border crossings as funnels, where people file through in orderly lines. Crossings like Kazungula are more like sieves. Small traders - usually women - just hop aboard the ferry and cross over for the day. Large vehicles, and those without the means to grease their way, have a harder time getting through.

In the Wealth of Nations, Adam Smith wrote "The tolls for the maintenance of a high road cannot with any safety be made the property of private persons." In his day, road maintenance was financed by tolls, but according to Smith:

At many turnpikes, it has been said, the money levied is more than double of what is necessary for executing, in the completest manner, the work which is often executed in very slovenly manner, and sometimes not executed at all.

Substitute border post for turnpike, and corrupt customs agents for private persons, and Smith's description could apply to modern Africa. There's a hold-up problem: any agent with the ability to control access to the network can create obstacles and hold up traffic, in an attempt to expropriate as much of the gains from trade as possible.

The journey to prosperity is long. There are no road maps, nor guaranteed recipes for success, but better border crossings are a step in the right direction.

Donald - actually the African Development Bank has made the development of one-stop border crossings a priority, so it's definitely on the radar screen. It's not rocket science to figure that the 16 land-locked African countries are unlikely to prosper economically if they're not able to get goods to and from ports.

But smooth border crossings require lots of different types of infrastructure - there's the physical infrastructure of roads and bridges and weigh stations and queues. There's the technological infrastructure - at a lot of these border posts, everything is written down by hand, and then keyed in manually - it's really strange to cross a border and have someone pull out a book and write your details down on it. Then there's the political infrastructure - good governance, clear and transparent rules and regulations, absence of graft. In some sense, if someone could figure out how to fix the border crossings, they'd have figured out how to fix so much of what hampers economic development.

RPLong - thank you. The interesting question is whether similar forces prevent better border crossings here, too. I'm thinking of, for example, the way that the owner of the Ambassador Bridge campaigned and lobbied against the building of a new and better bridge connecting Windsor and Detroit - again someone attempting to hold up traffic in order to protect his rents. The Canada/US border is also going more towards a front-of-the-line pass model, which would be expected to reduce the pressure for shorter crossing times. If those with power and influence can bypass the queue, they won't spend time and effort lobbying for shorter line-ups.

There was a similar article in the Economist a few years ago (god, was it 2002?: http://www.economist.com/node/1487583) on the travails of transporting a truck full of beer (Guinness, of all things) into the interior of the Cameroon. What should have been a day's drive became a multi-day epic owing to a combination of corrupt and officious police officers, lousy roads, bad weather, and lazy officials. Owing to the Economists inimitable style, it's an entertaining read, but a damned depressing one.

westslope - I hope that the post was clear: donor-built bridges can help, but are not enough. Borders are political creations - they're one of the key manifestations of the power and operation of the state. If the state is failing, border crossings are unlikely to work well - no matter how much donor cash is thrown at them. I think people have a better understanding of this now than they once did.

B.t.w., it's not western aid these days. China is playing an increasingly important role in African econ development - something that's definitely worth studying. Chinese organizations are among those financing the Kazungula Bridge.

Bob, thanks for the link. Yup - "the true ghastliness of third-world infrastructure". Though attempts to improve the infrastructure are often remarkably useless. E.g. the main road in Livingstone was just paved two or three years ago. Unfortunately the contractors - either to cut corners, or out of ignorance - used a form of tarmac that couldn't cope with heat. Consequently this nearly-new road has deep ruts in it already, and is in need of repair.

Frances: Yes, the Chinese to their credit want to trade with Africans. Not just treat them like cute puppy dogs.

I could be out of touch so if you have data that suggests western food aid has declined sharply over the years, please share. If you have data that shows that Canadian tariff barriers to the poorest Black African countries have come down over the past while, please share.

In the background, massive subsidies for American and European food continue to distort world food markets.

Kelvin: not that any of these roads is physically passable nor exempt of pirates, rebels and even worse policemen and soldiers.
One of my exes was there for the UN. She found it far worse than her preceding posting in Ivory Coast during the 2004-2006 civil war. She is now in Mali and find it refreshingly quiet....

Your link on the bridge construction notes that ferry availability due to poor maintenance averages 50% and that crossing time doubles during the rainy season! However, it also includes the info that new ferries aren't very expensive in comparison to new bridges. It calculates that there is significant economic value and a high rate of return available for bridge construction as evaluated over purchase of 2 new ferries, but does not evaluate an increased number of ferries or a higher-capacity ferry.

Benamery21 - interesting point. There are quite a few differences between an improved ferry and a bridge. I think the bridge would include new one-stop-border-crossings (something the African Development bank seems very keen on). Perhaps one could make the case that the decision to go with a bridge rather than a ferry is partly about changing bureaucratic structures, as well as physical ones? A bridge also might be a bit harder for small traders to cross than a ferry. It seems that the ferry is quite a porous border - while trucks wait for days, small traders can hop on more easily. That might change with a bridge. Certainly for foot passengers an improved ferry would be superior to a bridge.